JavaFX - waiting for task to finish - task

Question

I have a JavaFX application which instantiates several Task objects.
Currently, my implementation (see below) calls the behavior runFactory() which performs computation under a Task object. Parallel to this, nextFunction() is invoked. Is there a way to have nextFunction() "wait" until the prior Task is complete?
I understand thread.join() waits until the running thread is complete, but with GUIs, there are additional layers of complexity due to the event dispatch thread.
As a matter of fact, adding thread.join() to the end of the code-segment below only ceases UI interaction.
If there are any suggestions how to make nextFunction wait until its prior function, runFactory is complete, I'd be very appreciative.
Thanks,
// High-level class to run the Knuth-Morris-Pratt algorithm.
public class AlignmentFactory {
public void perform() {
KnuthMorrisPrattFactory factory = new KnuthMorrisPrattFactory();
factory.runFactory(); // nextFunction invoked w/out runFactory finishing.
// Code to run once runFactory() is complete.
nextFunction() // also invokes a Task.
...
}
}
// Implementation of Knuth-Morris-Pratt given a list of words and a sub-string.
public class KnuthMorrisPratt {
public void runFactory() throws InterruptedException {
Thread thread = null;
Task<Void> task = new Task<Void>() {
#Override public Void call() throws InterruptedException {
for (InputSequence seq: getSequences) {
KnuthMorrisPratt kmp = new KnuthMorrisPratt(seq, substring);
kmp.align();
}
return null;
}
};
thread = new Thread(task);
thread.setDaemon(true);
thread.start();
}

Answer 1

When using Tasks you need to use setOnSucceeded and possibly setOnFailed to create a logic flow in your program, I propose that you also make runFactory() return the task rather than running it:
// Implementation of Knuth-Morris-Pratt given a list of words and a sub-string.
public class KnuthMorrisPratt {
public Task<Void> runFactory() throws InterruptedException {
return new Task<Void>() {
#Override public Void call() throws InterruptedException {
for (InputSequence seq: getSequences) {
KnuthMorrisPratt kmp = new KnuthMorrisPratt(seq, substring);
kmp.align();
}
return null;
}
};
}
// High-level class to run the Knuth-Morris-Pratt algorithm.
public class AlignmentFactory {
public void perform() {
KnuthMorrisPrattFactory factory = new KnuthMorrisPrattFactory();
Task<Void> runFactoryTask = factory.runFactory();
runFactoryTask.setOnSucceeded(new EventHandler<WorkerStateEvent>() {
#Override
public void handle(WorkerStateEvent t)
{
// Code to run once runFactory() is completed **successfully**
nextFunction() // also invokes a Task.
}
});
runFactoryTask.setOnFailed(new EventHandler<WorkerStateEvent>() {
#Override
public void handle(WorkerStateEvent t)
{
// Code to run once runFactory() **fails**
}
});
new Thread(runFactoryTask).start();
}
}